Section, act June 12, 1917, ch. 27, 40 Stat. 144, related to purchases or services for the Geological Survey, was omitted as superseded. See sections 471 et seq. and 751 et seq. of Title 40, Public Buildings, Property, and Works, section 201 et seq. of Title 41, Public Contracts, and sections 2101 et seq., 2501 et seq., 2901 et seq., and 3101 et seq. of Title 44, Public Printing and Documents.